Reg

Hello everyone.

I did a quick search on this topic without finding much so here goes. I finally got the car running smooth tonite after a week of fiddling. New oil, fuel and air filters plus plugs. The timing was way out and allthough the car still pops a bit, the revs are much much free to run up the tach. Maybe it is slightly rich as I can see a slight bit of black smoke with a strong touch on the accelerator.

Anyways, I now hear a wobble noise at idle and if I put pressure with my hand on the fan cover I can feel that it may be a bearing on the cooling fan. Is this something that can be tightened or adjusted? Is it a usual wear item and can it be easily and cheaply replaced?

I have books, but have been in them the past few days and am just hoping I can get some plainer emglish answers or pointers from owners rather than the textbook jargin to a rookie (and certainly no mechanic) like me.

I had a hard time figuring out the timing until I had spoken to someone who had personally set the timing on one of these cars before and it was a great help.


Thanks!

Dial 911

Reg,
You don't really have a "bearing on the cooling fan." What you have is a fan on the shaft of the alternator. Your problem relates to the bearings in that alternator.

If you take off the fan belt and rotate the pulley with your hand, you may feel roughness as it rotates = a bad alternator bearing.

You should not operate the motor with this condition. If the bearing deteriorates further, the fan will, as you say, wobble. It will damage itself on the outer shroud in doing so. It could even disintegrate and do more damage to the engine etc.

A fan wobble, can also be caused by damage to the alternator shaft. Typically, this occurs by the incorrect use of the thin shims that are placed in front and behind the pulley, used to tension the fan belt. If you don't feel bearing roughness or play, this could be your problem.

The Pelican website offers a D-I-Y essay on how to pull the fan and alternator. You should then be able to have an auto electric repair shop replace the bearings. While they are doing that, it may be prudent to have them service the brushes and other components as well.

Reg

Thank you dial 911!

I will look at the fan belts adjustment. hopefully that is the problem. It seemded to just appear suddenly , allthough I may not have noticed it while having a rough running motor.

Dial 911

I might add, the Pelican tech site also has an article on how to tension the fan belt. The directions are in the Owners Manual too. It seems simple enough, but so many belts I've seen are way out of whack.

Bill Gregory

Reg,

One other thing to look at. There's a bolt up by the coil that holds the large strap that surrounds the metal fan case. If that bolt is too tight, it can force the fan case metal into an odd position, causing odd sounds from that area. You might try loosening it a bit to see if that affects the sounds.

Reg

Thanks Bill.

A fellow from RGR auto parts whom I have been getting some items from mentioned the same thing to me. We have been working in that area so I will be looking into that definately!

Howard

I just had one of my alternators rebuilt by a local auto electric shop and the cost was $125. FYI
One other thing to look at is whether the fan is making contact with the outer shroud. I purchased 3 used fan and shroud sets and at least one support strut was cracked on every shroud, this could cause the fan to contact the shroud if the belt is too tight.Again..fyi ! good luck!

Reg

I pulled the fan belt off (which was not that easy using a screwdriver as I am missing that special tool) and spun the fan loose without any belt installed and at that point I could feel and hear a slight worn sound of the shaft, could even move it slightly forward and back. I guess it is the alternator. My friend said it wasnt that bad and to focus on the road worthyness first. Thinking it was not serious enough to worry about if we are only driving it little and no big trips.

saint

Hi. If your alternaotr is worn, try one of these. I never liked any electrical parts that were 30 years old being fixed. www.aasesales.com

Dial 911

Reg,
Before you decide to take those "little" trips, just make sure the fan has not been rubbing on the shroud. With the belt still off, spin the fan slowly while looking around the inside circumference for rub marks. You'll probably need a flashlight.

And do the right thing by your 911 and buy the correct pulley holding wrench. You'll screw up the pulley otherwise.

Bill Gregory

Reg,

If you decide you need to replace your alternator, you have several choices. As already mentioned, you can have it rebuilt yourself, you can buy the Australian-built alternator for $395, the Porsche alternator (with 2 year warranty) is roughly $330 from Hendrick Porsche ($395 list,as I recall), or oem from Vertex for around $270 (don't know about warranty coverage). You can also find a rebuilt alternator from other sources, however, I haven't heard good things about their longevity. When I replaced mine I went with new.

Any of those alternators will have an onboard voltage regulator (as oppposed to the separate one you have today), and may require a resistor spliced on top of the alternator warning light on the dash. If you have access to the Porsche Parts and Technical Reference Catalog for 74-89 911's, they reprint the factory bulletin in there that tells how to do the retrofit. If you don't have access to it, send me an email, and I'll send you the part numbers you'll need.

Reg

Thanks again all!

The fan does not rub anywhere on the shroud. It spins freely , but has a slight bit of play that moves forward and backard more so than up and down.

we know the alternator is charging still, as the batteries would well be dead with all of the work we have been doing vs driving the car.

I am pretty sure its the bearing in the alternator.

The bummer is 300 US$ = $450 for me being in Canada!

The PO told me yesterday that the alternators can be a pain, meaning he must have had problems with it before. The pully looks very worn actually. The plate looks like its could be almost cracked. Or as if someone was having a very hard time removing the nut with the pin it it.

Is it ok to take a picture of parts of the car and post them on here?
I already posted two pictures and do not want to get in the bad books with the webmaster...being a new member and all!

Bill Gregory

Reg,

I have it on good word that pictures are very much OK to use here You can put up to 8 pictures on one post. If posting a picture would help the web board members to help you, then please post it!

Bill Gregory

Reg,

I have it on good word that pictures are very much OK to use here You can put up to 8 pictures on one post. If posting a picture would help the web board members to help you, then please post it!

Reg

Ok , I have a digi camera for work, so I will grab it and show some of what I am working with.